The hospital had been closed since a criminal gang attacked the facility in February.
The authorities had promised to reopen the hospital on Christmas Eve, but the same gang returned during the reopening ceremony and fired directly into the press conference being held on site.
In addition to the two killed journalists, seven more reporters were injured, according to Haiti's union for journalists, which equates the act with terrorism.
I extend my sympathies to the victims, the national police, and journalists, says Haiti's acting president Leslie Voltaire in a speech to the violence-ridden nation.
A notorious gang leader has taken responsibility for the attack, citing the reason that he did not approve of the hospital's reopening.
Haiti, one of the world's poorest countries, has been plunged into chaos since criminals took over large parts of the country. Approximately 85 percent of the capital Port-au-Prince is controlled by street gangs.
The gangs' looting and arson attacks on healthcare facilities and pharmacies have driven Haiti's healthcare system to the brink of collapse.
Several public institutions have been subjected to similar attacks, including the international airport and the country's two largest prisons.
